Magnetorheological damper

ABSTRACT

A magnetorheological damper, wherein the damper comprises a housing that is at least partially filed with a magnetorheological fluid, and a magnetorheological valve disposed within the housing. The valve includes a magnetically permeable core having at least one coil reservoir formed therein, and at least one conductor coil, wherein each conductor coil is disposed around a portion of the core within a respective one of the coil reservoir(s). The valve additionally includes a fluid flow path adjacent the conductor coil(s). The fluid flow path is structured and operable to allow the magnetorheological fluid to flow adjacent the conductor coil(s). The valve further includes at least one coil cover, wherein each coil cover is disposed over a respective one of the coil(s) such that the respective coil is protected from exposure to magnetorheological fluid flowing through the fluid flow path.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/209,930, filed Mar. 23, 2021, which is a continuation of U.S. patentapplication Ser. No. 16/025,662 (issued U.S. Pat. No. 10,995,816), filedJul. 2, 2018, which is a continuation of U.S. patent application Ser.No. 15/170,380 filed on Jun. 1, 2016. The disclosures of the aboveapplications/patents are incorporated herein by reference in theirentirety.

FIELD

The present teachings relate to vehicle suspensions, and moreparticularly to magnetorheological dampers for computer controlledvehicle suspension systems.

BACKGROUND

The statements in this section merely provide background informationrelated to the present disclosure and may not constitute prior art.

A critical performance criterion in control of a vehicle suspensionmagnetorheological (MR) damper is the control ratio. For high qualitysuspension performance, the MR damper needs to have a high controlratio. The control ratio is the maximum on-state force (e.g., themaximum force the damper can make with the fluid fully energized)relative to the minimum off-state force (e.g., the minimum force thedamper can make with no flux acting on the fluid) for a wide range ofdamper velocities. Generally, to achieve a high control ratio it isdesired to have an active length of a MR valve of the damper be as longas possible and an inactive length as short as possible. The activelength is the section of the MR valve where the fluid is energized by amagnetic field, whereas the inactive length is the section of the MRvalve where the fluid is not energized.

Known MR dampers typically have an energizing coil wherein the entirelength of its external faces is exposed to the MR fluid within thedamper. This subjects the coil to erosion by MR fluid and also defines arelatively long inactive length, e.g., an inactive length that issubstantially equal to the length of the coil. Due to the exposed coil,the active length of most known MR dampers is typically about 50% of thelongitudinal length of the valve, and hence, the inactive length of mostknown MR dampers is typically about 50% of the longitudinal length ofthe valve.

SUMMARY

A magnetorheological damper, wherein the damper comprises a housing thatis at least partially filed with a magnetorheological fluid, and amagnetorheological valve disposed within the housing. The valve includesa magnetically permeable core having at least one coil reservoir formedtherein, and at least one conductor coil, wherein each conductor coil isdisposed around a portion of the core within a respective one of thecoil reservoir(s). The valve additionally includes a fluid flow pathadjacent the conductor coil(s). The fluid flow path is structured andoperable to allow the magnetorheological fluid to flow adjacent theconductor coil(s). The valve further includes at least one coil cover,wherein each coil cover is disposed over a respective one of the coil(s)such that the respective coil is protected from exposure tomagnetorheological fluid flowing through the fluid flow path.

In various embodiments, each coil cover comprises a multi-section coilcover that includes at least one magnetically permeable sectionfabricated of a magnetically permeable material such that eachmagnetically permeable section provides a portion of an active length ofthe valve, and at least one magnetic isolator section fabricated of anon-magnetically permeable material such that each magnetic isolatorsection provides at least a portion of an inactive length of the valve.

This summary is provided merely for purposes of summarizing variousexample embodiments of the present disclosure so as to provide a basicunderstanding of various aspects of the teachings herein. Variousembodiments, aspects, and advantages will become apparent from thefollowing detailed description taken in conjunction with theaccompanying drawings which illustrate, by way of example, theprinciples of the described embodiments. Accordingly, it should beunderstood that the description and specific examples set forth hereinare intended for purposes of illustration only and are not intended tolimit the scope of the present teachings.

DRAWINGS

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present teachings in any way.

FIG. 1 is a side view of a vehicle having a suspension system includingat least one magnetorheological damper in accordance with variousembodiments of the present disclosure.

FIG. 2 is block diagram of a generic embodiment of themagnetorheological damper shown in FIG. 1 including a magnetorheologicalvalve, in accordance with various embodiments of the present disclosure.

FIG. 3 is a schematic of a cross-section of the generic embodimentmagnetorheological valve shown in FIG. 2 , in accordance with variousembodiments of the present disclosure.

FIG. 4 is an enlarged view of a portion of the schematic shown in FIG. 3, in accordance with various embodiments of the present disclosure.

FIG. 5 is an enlarged cross-sectional view of a portion of themagnetorheological valve shown in FIGS. 2, 3 and 4 , in accordance withvarious embodiments of the present disclosure.

FIG. 6 is an isometric cross-sectional view of the magnetorheologicalvalve shown in FIGS. 2, 3, 4 and 5 , in accordance with variousembodiments of the present disclosure.

FIG. 7 is an isometric cross-sectional view of the magnetorheologicalvalve shown in FIGS. 2, 3, 4 and 5 , in accordance with various otherembodiments of the present disclosure.

FIG. 8 is an isometric cross-sectional view of the magnetorheologicalvalve shown in FIGS. 2, 3, 4 and 5 , in accordance with yet othervarious embodiments of the present disclosure.

FIG. 9 is a side cross-sectional view of 2, 3, 4 and 5, in accordancewith still yet other various embodiments of the present disclosure.

FIG. 10 is a side cross-sectional view of 2, 3, 4 and 5, in accordancewith yet still other various embodiments of the present disclosure.

FIG. 11 is a side cross-sectional view of 2, 3, 4 and 5, in accordancewith further other various embodiments of the present disclosure.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of drawings.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is in no wayintended to limit the present teachings, application, or uses.Throughout this specification, like reference numerals will be used torefer to like elements. Additionally, the embodiments disclosed beloware not intended to be exhaustive or to limit the invention to theprecise forms disclosed in the following detailed description. Rather,the embodiments are chosen and described so that others skilled in theart can utilize their teachings. As well, it should be understood thatthe drawings are intended to illustrate and plainly disclose presentlyenvisioned embodiments to one of skill in the art, but are not intendedto be manufacturing level drawings or renditions of final products andmay include simplified conceptual views to facilitate understanding orexplanation. As well, the relative size and arrangement of thecomponents may differ from that shown and still operate within thespirit of the invention.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this disclosure belongs. The terminology used herein isfor the purpose of describing particular example embodiments only and isnot intended to be limiting. As used herein, the singular forms “a,”“an,” and “the” may be intended to include the plural forms as well,unless the context clearly indicates otherwise. The terms “comprises,”“comprising,” “including,” and “having,” are inclusive and thereforespecify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof. The method steps,processes, and operations described herein are not to be construed asnecessarily requiring their performance in the particular orderdiscussed or illustrated, unless specifically identified as an order ofperformance. It is also to be understood that additional or alternativesteps can be employed.

When an element, object, device, apparatus, component, region orsection, etc., is referred to as being “on,” “engaged to or with,”“connected to or with,” or “coupled to or with” another element, object,device, apparatus, component, region or section, etc., it can bedirectly on, engaged, connected or coupled to or with the other element,object, device, apparatus, component, region or section, etc., orintervening elements, objects, devices, apparatuses, components, regionsor sections, etc., can be present. In contrast, when an element, object,device, apparatus, component, region or section, etc., is referred to asbeing “directly on,” “directly engaged to,” “directly connected to,” or“directly coupled to” another element, object, device, apparatus,component, region or section, etc., there may be no interveningelements, objects, devices, apparatuses, components, regions orsections, etc., present. Other words used to describe the relationshipbetween elements, objects, devices, apparatuses, components, regions orsections, etc., should be interpreted in a like fashion (e.g., “between”versus “directly between,” “adjacent” versus “directly adjacent,” etc.).

As used herein, the term “and/or” includes any and all combinations ofone or more of the associated listed items. For example, A and/or Bincludes A alone, or B alone, or both A and B.

Although the terms first, second, third, etc. can be used herein todescribe various elements, objects, devices, apparatuses, components,regions or sections, etc., these elements, objects, devices,apparatuses, components, regions or sections, etc., should not belimited by these terms. These terms may be used only to distinguish oneelement, object, device, apparatus, component, region or section, etc.,from another element, object, device, apparatus, component, region orsection, etc., and do not necessarily imply a sequence or order unlessclearly indicated by the context.

Moreover, it will be understood that various directions such as “upper”,“lower”, “bottom”, “top”, “left”, “right”, “first”, “second” and soforth are made only with respect to explanation in conjunction with thedrawings, and that components may be oriented differently, for instance,during transportation and manufacturing as well as operation. Becausemany varying and different embodiments may be made within the scope ofthe concept(s) herein taught, and because many modifications may be madein the embodiments described herein, it is to be understood that thedetails herein are to be interpreted as illustrative and non-limiting.

The term code, as used herein, can include software, firmware, and/ormicrocode, and can refer to one or more programs, routines, functions,classes, and/or objects. The term shared, as used herein, means thatsome or all code from multiple modules can be executed using a single(shared) processor. In addition, some or all code from multiple modulescan be stored by a single (shared) memory. The term group, as usedabove, means that some or all code from a single module can be executedusing a group of processors. In addition, some or all code from a singlemodule can be stored using a group of memories.

The apparatuses/systems and methods described herein can be implementedby one or more computer programs executed by one or more processors. Thecomputer programs include processor executable instructions that arestored on a non-transitory, tangible, computer-readable medium. Thecomputer programs can also include stored data. Non-limiting examples ofthe non-transitory, tangible, computer-readable medium are nonvolatilememory, magnetic storage, and optical storage.

FIG. 1 illustrates, by way of example, a vehicle 10 that includes asuspension system (generally indicated at 14) that comprises amagnetorheological damper, in accordance with various embodiments of thepresent disclosure. The vehicle 10 can be any vehicle that generallyincludes a chassis (or frame) 22 to which a body 26 is connected (thebody including such components as a front cowl, fenders, doors, sidepanels, quarter panels, a dash panel, etc.), two or more wheels 30, andthe suspension system 14 that operatively connects the wheels 30 to thechassis 22 and/or portions of the body 26. For example, it is envisionedthat the vehicle 10 can be a car, truck, motorcycle, sport utilityvehicle (SUV), bus, recreational vehicle (RV), or any other vehicledesignated for use on roadways, or vehicle 10 can be any full sizeand/or lightweight and/or utility and/or low-speed vehicle that is notdesignated for use on roadways, such as a maintenance vehicle, a cargovehicle, a shuttle vehicle, a golf car, an all-terrain vehicle (ATV), autility-terrain vehicle (UTV), a recreational off-highway vehicle (ROV),a side-by-side vehicle (SSV), a worksite vehicle, a buggy, a snowmobile,a tactical vehicle, etc.

Referring now to FIGS. 1, 2 and 3 , in various embodiments, thesuspension 14 includes at least one magnetorheological (MR) damper 34.Each MR damper 34 operatively connects a respective one of the wheels tothe vehicle chassis 22 and/or body 26. Although the suspension 14 caninclude more than one MR damper 34, for simplicity and clarity, only asingle MR damper 34 of the present disclosure will be described herein.The MR damper 34 generally includes housing 38 at least partially filledwith a magnetorheological (MR) fluid 40, a piston 42 disposed within thehousing 38, a piston rod 46 connected to the piston 38, and amagnetorheological (MR) valve 50. The piston rod 46 extends through anend of the housing 38 and is operatively connectable to either arespective wheel 30 of the vehicle 10 or the chassis 22 and/or a portionof the body 26. Depending on the connection location of the piston rod46, an opposing end of the housing 38 is operatively connectable to theother of the respective wheel 30 or the chassis 22 and/or a portion ofthe body 26. Accordingly, when the MR damper 34 is mounted between awheel 30 and the chassis 22 and/or a portion of the body 26, travel ofthe vehicle 10 across a terrain will cause the wheels 30 and the body 26to move relative to each other such that the MR damper 34 is subject tocompression (or jounce) and extension (or rebound), whichbidirectionally moves the piston 42 within the housing 38.

Compression (or jounce) and extension (or rebound) of the MR damper 34causes the piston 42 to move within the damper housing 38. As the piston42 moves within the housing 38 the MR fluid 40 is forced to flow throughthe MR valve 50. More specifically, the MR fluid 40 is forced to flowthrough at least one fluid flow channel (or elongated orifice) 54 of theMR valve 50. The channel(s) 54 is/are disposed, provided or formedbetween a magnetically permeable core 58 and a magnetically permeableflux ring 62 of the valve 50. The MR valve 50 additionally includes atleast one conductor coil 66 that is disposed within the core 58 and inclose proximity of the channel(s) 54. As the MR fluid 40 is forcedthrough the channel(s) 54 and adjacent the conductor coil(s) 66, theconductor coil(s) 66 is/are controllably energized to generate magneticflux between the core 58 and the flux ring 62 through which the MR fluid40 flows. The one or more areas of the channel(s) 54 through which themagnetic flux is directed are referred to herein as the active sectionsof the channel(s) 54. Conversely, the one or more areas of thechannel(s) 54 where no magnetic flux is directed, e.g., are not within aflux field, are referred to herein as the inactive sections of thechannel(s) 54.

As the MR fluid 40 flows though the active sections of the channel(s)54, and magnetic flux is being generated and directed across activesections, the flow properties of the MR fluid 40 are altered tocontrollably increase and decrease the pressure drop along thechannel(s) 54. Particularly, As the MR fluid 40 flows though the activesections of the channel(s) 54 the shear strength, or shear stress, ofthe MR fluid 40 is controllably altered, as a result of the controlledstrength of the magnetic flux. More particularly, when the MR fluid 40flows through the flux field directed across the active sections of thechannel(s) 54, metal particles within the MR fluid 40 align according tothe flux field lines, thereby changing the shear strength of the MRfluid 40, making the MR fluid 40 “stiff”, such that the MR fluid 40 doesnot flow through the channel(s) 54 as readily and easily as when it isnot exposed to the flux field. By controlling the strength of themagnetic flux directed through the active sections of the channel(s) 54,the pressure drop along the channel(s) 54 can be controlled, therebycontrolling the speed, or velocity, of movement of the piston 42 withinthe housing 38, thereby controlling the speed, or velocity, of thecompression (or jounce) and extension (or rebound) of the MR damper 34,and thereby controlling the speed, or velocity of the movement of thewheels 30 and the body 26 relative to each other to attenuate undesiredshock or vibration of the vehicle 10.

In various embodiments, operation of the MR valve 50, e.g., generationof the magnetic flux field, is controlled by one or more MR valvecontrol algorithms executed by a damper controller, which can be astand-alone controller, or part of one or more computer based vehiclecontrol system(s). For example, in various embodiments the dampercontroller can be a hardware based module that is structured andoperable to implement the MR valve control algorithm(s). For example, itis envisioned that the damper controller can comprise one or more, or bepart of, application specific integrated circuit(s) (e.g., ASIC(s)),combinational logic circuit(s); field programmable gate array(s) (FPGA);processor(s) (shared, dedicated, or group), that execute the MR valvecontrol algorithm(s) to provide the MR damper functionality describedherein; or a combination of some or all of the above, such as in asystem-on-chip. Alternatively, the damper controller can be part of oneor more computer based vehicle control system(s) wherein the MR valvecontrol algorithm(s) are stored in electronic memory of the system(s)and executed by one or more processor of the system(s). Execution ofvehicle control software and algorithms, such as the MR valve controlalgorithms, is well understood by those skilled in the art, and need notbe described further herein.

As described above, to improve suspension performance of an MR damper,e.g., MR damper 34, is it beneficial and desirable to have a highcontrol ratio. As also described above, the control ratio is the maximumon-state force relative to the minimum off-state force. As used herein,the on-state of the MR fluid 40 is when the MR fluid 40 is exposed tothe magnetic flux field, and the off-state of the MR fluid 40 is whenthe MR fluid 40 is not exposed to the magnetic flux field. Hence, themaximum on-state force of the MR fluid 40 is the maximum shear strengthof the MR fluid 40 that relates to the maximum magnetic flux that can begenerated by the respective coil(s) 66, core 58 and flux ring 62. Thatis, the maximum on-state force of the MR fluid 40 is the maximumresistive force to movement of the piston 42 within the housing 38 thatis generated by the MR valve 50 when the MR fluid 40 is fully energizedby the maximum flux field that can be generated by the respectivecoil(s) 66, core 58 and flux ring 62. Similarly, the minimum on-state ofthe MR fluid 40 is minimum shear strength of the MR fluid 40 thatrelates to the minimum magnetic flux, e.g., zero or no magnetic flux,that can be generated by the respective coil(s) 66, core 58 and fluxring 62. That is, the minimum on-state force of the MR fluid 40 is theminimum resistive force to movement of the piston 42 within the housing38 that is generated by the MR valve 50 when the MR fluid 40 is not, orminimally, energized relative to the minimum flux field that can begenerated by the respective coil(s) 66, core 58 and flux ring 62.

Furthermore, as described above, to achieve a high control ratio it isdesirable to have a total active length of the MR valve, e.g., MR valve50, be as long as possible and a total inactive length be as short aspossible. As used herein, the total active length the MR valve 50, isthe cumulative length of the one or more active sections of the channel54, e.g., the cumulative length of the sections of the channel where theMR fluid 40 is energized by a magnetic field. For example, the totalactive length of the channel 54 shown in FIG. 3 is the cumulative lengthof active lengths 70A and 70B. Similarly, as used herein, the inactivelength the MR valve 50, is the cumulative length of the one or moreinactive sections of the channel 54, e.g., the cumulative length of thesections of the channel where the MR fluid 40 is not energized by amagnetic field. For example, the total inactive length of the channel 54shown in FIG. 3 is the length of inactive length 74.

As used herein, the term length will be understood to refer todimensions parallel with and/or collinear to a longitudinal, axis of thefluid flow channel 54 along which the MR fluid flows.

As further described above, the entire length of the external face ofthe conductor coil(s) of prior art MR valves is typically open to fluidflow channel and therefore exposed to MR fluid as the fluid flowsthrough the channel, thereby subjecting coil(s) to erosion by the MRfluid. Additionally, due to the exposure of the entire face of thecoil(s) to channel and MR fluid, the properties and characteristics ofmagnetic flux fields, the flux field generated by such prior art coil(s)will not be directed across the channel and through the fluid directlyadjacent the face of the coil(s). Therefore, the inactive length of suchprior art valves is substantially equal to the length of the coilface(s), which creates a relatively long inactive length of the valve,which affects the control ratio of the valve, e.g., limits the maximumcontrol ratio.

Referring now to FIGS. 2, 3 and 4 , further to the description above, invarious embodiments, the magnetically permeable core 58 comprises atleast one coil reservoir 78 formed therein and each conductor coil 66 isdisposed around a portion of the core 58 within a respective one of thecoil reservoir(s) 78. Additionally, in various embodiments, the MR valve50 comprises at least one coil cover 82. In various embodiments, eachcoil cover 82 scan be disposed over at least a portion of the externalface 86 of a respective one of the coil(s) 66 (e.g., the face of thecoil 66 closest to the fluid flow channel 54). For example, in variousembodiments, each coil cover 82 is disposed over the entire externalface 86 of a respective one of the coil(s) 66 such that the respectivecoil 66 is protected from exposure to the MR fluid 40 within the fluidflow channel 78. In various implementations, each coil cover 82 isrecessed within the core 58, and extends across the entire coilreservoir 78 and coil external face 86 such that an external face 90 ofeach coil cover 82 (e.g., the face of the cover 82 exposed to the fluidfollow channel 54 and the MR fluid 40 therein) is flush with an internalface 94 of the fluid flow channel 54. Therefore, the flow of the MRfluid 40 through the fluid flow channel 54 is not disturbed, impeded,disrupted or interfered with by the respective coil cover 82.

Referring now to FIGS. 3, 4 and 5 , in various embodiments, each coilcover 82 is a multi-section coil cover comprising at least one activesection 98 disposed over a portion of the respective coil 66 andfabricated of a magnetically permeable material, and at least oneinactive section 102 disposed over a portion of the respective coil 66and fabricated of a non-magnetically permeable material. Since theactive section(s) 98 is/are fabricated of a magnetically permeablematerial, the flux field generated by the respective coil 66 will flowthrough the entire length of the active section(s) 98 and be directedacross the fluid flow channel 54 into the flux ring 62 along the lengthof the active section(s) 98. Conversely, since the inactive section(s)102 is/are fabricated of a non-magnetically permeable material, theinactive section(s) 102 provide a magnetic isolator such that the fluxfield generated by the respective coil 66 will not flow through theinactive section(s) 102 and not be directed across the fluid flowchannel 54 along the length of the inactive section(s) 102. Hence, theactive section(s) 98 of the coil cover 82 will provide at least aportion of the total active length of the MR valve 50, and the inactivesection(s) 102 will provide at least a portion of the total inactivelength.

Moreover, by disposing the active section(s) 98 of the coil cover 82over a portion of the respective coil 66, the active length of the fluidflow channel 54 (and hence, the active length of the MR valve 50) issubstantially greater than the active length of known MR valves, andfurthermore, the inactive length of the fluid flow channel 54 (andhence, the inactive length of the MR valve 50) is substantially smallerthan the inactive length of known MR valves. Therefore, the maximumcontrol ratio of the MR valve 50 (e.g., the maximum on-state forcerelative to the minimum off-state force) can be greatly increased fromthat of known MR valves. Specifically, by disposing the activesection(s) 98 of the coil cover 82 over a portion of the respective coil66, the active length of the fluid flow channel 54, and hence, theactive length of the MR valve 50, is extended beyond the portion/lengthof the channel 54 that is adjacent the core 58. For example, as shown inFIG. 5 , the active length 70A comprises the core active length 70A1where the flux field (see FIG. 3 ) is generated through and directedacross the fluid flow channel 54 by the core 58, plus the cover activelength 70A2 where the flux field (see FIG. 3 ) is additionally generatedthrough and directed across the fluid flow channel 54 by the activecover section 98; and further, the active length 70B comprises the coreactive length 70B1 where the flux field is generated through anddirected across the fluid flow channel 54 by the core 58, plus the coveractive length 70B2 where the flux field is generated through anddirected across the fluid flow channel 54 by another active coversection 98. Accordingly, the total active length of the example MR valve50 shown in FIG. 5 is the active length 70A (e.g., core active length70A1 plus cover active length 70A2) plus the active length 70B (e.g.,core active length 70B1 plus cover active length 7062). Additionally,the total inactive length of the example MR valve 50 shown in FIG. 5 ismerely the length of the inactive section 102.

As illustrated, in various embodiments, the total or comprehensivelength of the active section(s) 98 of the coil cover 82 can besubstantially greater than the total or comprehensive length of theinactive section(s) 102. For example, in various embodiments, thecomprehensive length of the active section(s) 98 can be 60% to 95% ofthe total length of the coil cover 82, and the comprehensive length ofthe inactive section(s) 102 can be 5% to 40% of the total length of thecoil cover 82. Moreover, due to the active section(s) 98 of the coilcover 82, the total active length of the MR valve 50 can besubstantially greater than the total inactive length of the MR valve 50.For example, in various embodiments that total active length of the MRvalve 50 can be 60% to 95% of the total length of the fluid flow channel54, and the total inactive length of the MR valve 50 can be 5% to 40% ofthe total length of the fluid flow channel 54. Furthermore, since theon-state and off-state forces of the MR valve 50 are directly related tothe total active length and the total inactive length, respectively, theincreased total active length and the decreased total inactive lengthprovided by the multi-section coil cover 82, MR valve 50 can beconfigured or structured to have a control ratio that is considerablyhigher than known MR valve.

It should be noted, however, that the active section(s) 98 and inactivesection(s) 102 of the coil cover 82 can have any desired length suchthat, should it be desirable, the comprehensive length of the inactivesection(s) 102 can be greater than the comprehensive length of theactive section(s) 98. For example, should it be desirable, thecomprehensive length of the inactive section(s) 102 can be as much as90% to 95% of the total length of the coil cover 82, while thecomprehensive length of the active section(s) 98 can be little 5% to 10%of the total length of the coil cover 82.

Referring now to FIGS. 6, 7 and 8 , in various embodiments the MR valve50 can be incorporated in the piston 42 of the MR damper 34. That is, insuch embodiments, the piston 42 comprises the MR valve 50.

Referring particularly to FIGS. 6 and 7 , in various implementationswherein the piston 42 comprises the MR valve 50, the flux ring 62comprises an annular ring sized to fit within an interior of the damperhousing 38 such that the MR fluid 40 (not shown) cannot pass between theflux ring 62 and the housing 38. In various instances, the MR damper 34can include a sealing device (not shown), e.g., one or more O-ring,disposed between the flux ring 62 and the housing 38 to seal theinterface therebetween so that MR fluid 40 cannot flow between the fluxring 62 and the housing 38. Additionally, in such implementations, thecore 58 is cylindrically shaped and centrally disposed within theannular flux ring 62 such that an annular fluid flow channel 54 isdefined between the flux ring 62 and the core 58. The cylindrical core58 can comprise one or more core sections that are connectable ormateable to provide the core 58. The at least one coil reservoir 78 canbe formed within one or more of the core sections and the conductorcoil(s) 66 is/are disposed around a portion of the core 58 within arespective coil reservoir 78. Further, in such implementations, thepiston 42 includes at least one non-magnetically permeable end cap 106disposed on at least one end of the piston 42. The end cap(s) 106 areconnected, or mounted, to both the flux ring 62 and the core 58 suchthat the annular fluid flow channel 54 is maintained therebetween andhas a consistent width W throughout the channel 54. The end cap(s) 106is/are fabricated of a non-magnetically permeable material and comprisea plurality of orifices 110 aligned with the fluid flow channel 54 toallow the MR fluid 40 (not shown) to flow through fluid flow channel 54as the piston 42 moves within the housing 38.

As illustrated by way of example in FIG. 6 , in various embodiments thecylindrical core 58 can comprise a plurality of cylindrical coresections that are connectable or mateable to provide the core 58. Forexample, the core 58 can include a first core section 58A and a secondcore section 58B. As described above, in various embodiments, each coilcover 82 can be a multi-section coil cover comprising at least oneactive section 98 disposed over a portion of the respective coil 66 andfabricated of a magnetically permeable material, and at least oneinactive section 102 disposed over a portion of the respective coil 66and fabricated of a non-magnetically permeable material. For example, asillustrated in FIG. 6 , in various implementations, the first coresection 58A can be formed or fabricated to comprise a magneticallypermeable active section 98 (e.g., a first active section) that isintegrally formed therewith and extends over a first portion of therespective coil reservoir 78 such that the active section 98 is disposedover a first portion of the respective conductor coil 66. In suchimplementations, the cover 82 can include an inactive section 102 thatcomprises a magnetic isolator band disposed over a second portion of therespective conductor coil 66. It is envisioned that, in variousembodiments, the first and second portions of the coil 66 can comprisethe entire external coil face 90 such that the active section 98 (e.g.,the first active section) extends over the entire coil face 90 exceptfor the portion of the coil face 90 covered by the inactive section 102.

Alternatively, in various other embodiments, the second core section 58Bcan be formed or fabricated to comprise another magnetically permeableactive section 98 (e.g., a second active section) that is integrallyformed therewith and extends over a third portion of the respective coilreservoir 78 such that the active section 98 (e.g., the second activesection) is disposed over a third portion of the respective conductorcoil 66. In such embodiments, the inactive section 102 can be disposedaround a longitudinal center portion of the coil face 90, and the activesections 98 (e.g., the first and second active sections) can be disposedover the substantially equal length remaining portions of the coil face90 on both sides of the inactive section 102 of the cover 82.

As illustrated by way of example in FIG. 7 , in various embodiments thecylindrical core 58 can comprise a single piece core 58 or comprise aplurality of cylindrical core sections that are connectable or mateableto provide the core 58. As described above, in various embodiments, eachcoil cover 82 can be a multi-section coil cover comprising at least oneactive section 98 disposed over a portion of the respective coil 66 andfabricated of a magnetically permeable material, and at least oneinactive section 102 disposed over a portion of the respective coil 66and fabricated of a non-magnetically permeable material. For example, asillustrated in FIG. 7 , in various implementations, the multi-sectioncoil cover 82 can be separate and independent from (e.g., not integrallyformed with) the core 58. For example, the multi-section coil cover 82can include a first active section 98 comprising a first band disposedover a first portion of the respective conductor coil 66, the inactivesection comprising a magnetic isolator band disposed over a secondportion of the conductor coil 66, and a second active section comprisinga second band disposed over a third portion of the conductor coil 66. Invarious implementations, the inactive section 102 can be disposed arounda longitudinal center portion of the coil face 90, and the first andsecond active sections 98 can be disposed over the substantially equallength remaining portions of the coil face 90 on both sides of theinactive section 102 of the cover 82.

Alternatively, in various other implementations, the inactive section102 can be disposed around the coil face 90 at a longitudinal locationother than the center portion of the coil face 90, and the first andsecond active sections 98 can be disposed over the unequal lengthremaining portions of the coil face 90 on both sides of the inactivesection 102 of the cover 82. In still other implementations, it isenvisioned that the multi-section coil cover 82 can include a pluralityof the inactive sections 102 comprising a plurality of magnetic isolatorbands disposed over a plurality of portions of the conductor coil 66,and three or more of active sections 98 disposed over a plurality ofportions of the conductor coil 66, at least one of the active sections98 being disposed between two adjacent inactive sections 102.

Although FIGS. 6 and 7 illustrate example embodiments of the MR valve 50comprising the piston 42 having the annular flux ring 62 and the core 58(e.g., single piece or multi-piece core 58) disposed within the fluxring 62 to define the annular fluid flow channel 54, wherein the MRvalve 50 includes only a single conductor coil 66 and a single coilcover 82 (e.g., a multi-section cover 82), it is envisioned that invarious embodiments, the MR valves 50 of FIGS. 6 and 7 can includes aplurality of conductor coils 66 disposed within the core 58 and aplurality of respective coil covers 82, wherein each cover 82 isdisposed over a respective one of the coils 66 (as described below withregard to FIG. 8 ). Still further, it is envisioned that in variousembodiments of the piston MR valve 50 illustrated and described withregard to FIGS. 6 and 7 , the annular flux ring 62, as illustrated, canbe eliminated and the cylindrical housing 38 can provide or comprise theflux ring 62 (as described below with regard to FIG. 8 ).

Referring now to FIG. 8 , in various embodiments, wherein the piston 42of the MR damper 34 comprises the MR valve 50 and the cylindricalhousing 38 can comprise the flux ring 62. That is, in such embodimentsthe housing 38 can be fabricated from a magnetically permeable materialand comprise the flux ring 62 of the MR valve 50. In such embodiments,the core 58 is cylindrically shaped and centrally disposed within theannular housing/flux ring 38/62 such that the annular fluid flow channel54 is defined between the housing/flux ring 38/62 and the core 58. Insuch embodiments, the annular fluid flow channel 54 can have a largerannular diameter (e.g., the diameter defined by the diameter of the core58), and a narrower width W than the embodiments shown in FIGS. 6 and 7, thereby reducing the off-state force and increasing the on-state forceof the MR fluid flowing through the channel 54, which in turn, furtherincreases the control ratio of the MR valve 34.

The core can be a single piece core, as illustrated by way of example,or a multi-piece core having two or more core sections that areconnectable or mateable to provide the core 58. Additionally, in suchembodiments, the MR valve 50 can include a single end cap 106 connectedto a distal end of the core 58 (e.g., the end opposite the piston rod46), wherein the end cap 106 comprises a scalloped peripheral edgecomprising a plurality of semi-circular openings 114 aligned with thefluid flow channel 54 to allow the MR fluid 40 (not shown) to flowthrough fluid flow channel 54 as the piston 42 moves within the housing38. Additionally, in various embodiments, the MR valve 50 can comprise aplurality of coil reservoirs 78 formed within the core 58 and aplurality of conductor coils 66, wherein each conductor coil 66 isdisposed around a portion of the core 58 within a respective one of thecoil reservoirs 78. In such embodiments, the MR valve 50 additionallyincludes a multi-section coil cover 82 comprising a plurality ofinactive sections 102 and three or more active sections 98 disposedbetween and/or adjacent the inactive sections 102.

Referring now to FIGS. 5, 6, 7 and 8 , it should be noted that invarious embodiments wherein the housing 38 comprises the flux ring 62,as shown by way of example in FIG. 8 , the MR damper 34 can reject heatquicker and easier than the embodiments wherein the MR damper 34includes a flux ring 62 that is disposed within the housing 38, as shownby way of example in FIGS. 6 and 7 . Particularly, having the housing 38function as the flux ring 62 provides a shorter dissipation path for theheat generated within the MR damper 34. More particularly, the exposureof the outside of the housing to the ambient environment helps maintainthe housing/flux ring 38/62 at a cooler temperature such that thehousing/flux ring 38/62 will absorb and dissipate the generated heatmore efficiently.

Additionally, in various embodiments, the ends 54A and 54B of the fluidflow channel 54 can be chamfered, angled, funnel shaped or include abezel to provide a larger diameter at the ends 54A and 54B from that ofa central portion of channel 54. The chamfered, angled, funnel shaped orbezelled ends 54A and 54B are structured and operable to allow the MRfluid to enter and exit the channel 54 more easily and with lessturbulence and/or disruption, thereby increasing the on-state force, anddecreasing the off-state force of the MR fluid flowing through thechannel 54, which in turn, further increases the control ratio of the MRvalve 34. Additionally, in various implementations, the orifices 110and/or the openings 114 of the end cap(s) 106 can be chamfered, angled,funnel shaped or include a bezel to reduce the turbulence and/ordisruption of the MR fluid entering and exiting the channel 54.

Referring now to FIG. 9 , in various embodiments, the MR damper 34 cancomprise an inner cylindrical body 118 that defines a cylindricalchamber 120 that is at least partially filled with MR fluid 40 (notshown) and in which the piston 42 is disposed. The inner cylindricalbody 118 is centrally disposed within an outer cylindrical housing 122such that an outer annular chamber 126 is defined between the innercylindrical body 118 and the outer cylindrical housing 122. The outerannular chamber 126 is at least partially filled with MR fluid 40 and isfluidly connected with the inner cylindrical chamber 120 via windows 130formed in the ends of the inner cylindrical body 118. In suchembodiments, the MR valve 50 is disposed within the outer annularchamber 126. More particularly, in such embodiments, the core 58comprises and annular (single piece or multi-piece) core having one ormore coil reservoir 78 formed therein, each reservoir having arespective conductor coil 66 disposed therein as described above withregard to FIGS. 1, 2, 3, 4, 5, 6, 7 and/or 8 . Additionally, the MRvalve 50 further includes a coil cover 82 disposed over each of at leastone respective coil 66, wherein each coil cover 82 can be a single pieceor a multi-section coil cover as described above with regard to FIGS. 1,2, 3, 4, 5, 6, 7 and/or 8 . In various embodiments, the outercylindrical housing 122 can comprise the flux ring 62, as describedabove with reference to FIG. 8 , such that the annular fluid flowchannel 54 is defined between the core 58 and the outer cylindricalhousing/flux ring 122/62. Alternatively, although not shown, it isenvisioned that the MR valve 50 can include a flux ring 62 that isseparate from the outer cylindrical housing 122, as described above withreference to FIGS. 6 and 7 .

In operation, the MR fluid 40 is moved within the inner cylindricalchamber 120 as the piston 42 is bidirectionally moved within the innercylindrical chamber 120. The MR fluid 40 then passes through the windows130 and into the outer annular chamber 126 at a respective end of theinner cylindrical body 118. Consequently, the MR fluid 40 is forcedthrough the annular fluid flow channel 54 where the shear strength, orshear stress, of the MR fluid 40 is controllably altered as a result ofthe controlled strength of the magnetic flux generated by coil(s) 66, asdescribed above. Accordingly, the compression (or jounce) and extension(or rebound) of MR damper 34 can be controlled. Moreover, when the coilcover(s) 82 is/are multi-section covers, as described herein, thecontrol ratio of the MR valve 50, and hence the MR damper 34, issignificantly increased.

Referring now to FIG. 10 , in various embodiments, the MR damper 34 cancomprise a cylindrical body 134 having a valve head 138 formed ordisposed at a distal end thereof. The valve head 138 comprises an outerhousing 140 and an inner wall 142 that define an annular recess 146therebetween. The outer housing 140 and inner wall 142 can each beconnected to the cylindrical body 134, integrally formed with thecylindrical body 134, or be combination thereof. The valve head 138further includes an end wall 150 that seals the end of the MR damper 34,and a separator piston 154 disposed within the valve head 138. Theseparator piston 154 defines a MR fluid chamber 158 disposed on one sideof the separator piston 154 and a gas chamber 162 disposed on the otherside of the separator piston 154. The MR fluid chamber 158 includes theannular recess 146 formed between the outer housing 140 and the innerwall 142 of the valve head 138. The MR valve piston 42 is disposedwithin the interior of the cylindrical body 134. The portion of thecylindrical body interior disposed on the opposite side of the piston 42from the piston rod 46 is at least partially filled with MR fluid 40(not shown).

In such embodiments, the MR valve 50 includes a generally cup-shapedcore positioner 160 having an annular wall 166 that is disposed withinthe annular recess 146 such that a substantially U-shaped annular fluidflow channel 54 is defined between annular wall 166 of the corepositioner 160, a portion of the outer housing 140, and the inner wall142. Moreover, an annular core 58 is integrally formed with, or disposedon the annular wall 166 of the core positioner 160 such that the core 58is positioned within the annular recess 146 such that the substantiallyU-shaped annular fluid flow channel 54 passes along both an interiorside of the core 58 (e.g., the side facing the inner wall 142) and anexterior side of the core 58 (e.g., the side facing the outer housing140). Still further, the annular core 58 includes one or more coilreservoir 78 formed therein. A respective conductor coil 66 is disposedwithin each reservoir 78 such that, when energized, each coil 66 willgenerate a magnetic flux field that will be directed across the U-shapedannular fluid flow channel 54 along the portion of the channel 54passing between core/coil 58/66 and the outer housing 140, andadditionally directed across the U-shaped annular fluid flow channel 54along the portion of the channel 54 passing between the core/coil 58/66and the inner wall 142. Still yet further, the MR valve 50 of suchembodiments includes a pair of coil covers 82, wherein one coil cover 82is disposed over the interior side of the respective coil 66 (e.g., theside facing the inner wall 142) and the other coil cover 82 is disposedover the exterior side of the core 58 (e.g., the side facing the outerhousing 140). Each coil cover 82 can be a single piece or amulti-section coil cover as described above with regard to FIGS. 1, 2,3, 4, 5, 6, 7 and/or 8 . In various embodiments, the valve head outerhousing 140 and inner wall 142 can comprise flux rings. In various otherembodiments, the MR valve 50 can comprise flux rings 62 be independentstructures disposed between the core 58 and respective outer housing 140and inner wall 142.

In operation, when the MR damper 34 is compressed (e.g., jounce motion)the MR fluid 40 is moved within the cylindrical body 134 as the piston42 is moved toward the MR valve 50. Consequently, the MR fluid 40 isforced through the substantially U-shaped annular fluid flow channel 54where the shear strength, or shear stress, of the MR fluid 40 iscontrollably altered, as a result of the controlled strength of themagnetic flux generated by coil(s) 66 and directed across both theportion of the channel 54 passing between the core/coil 58/66 and theouter housing 140, and the portion of the channel 54 passing between thecore/coil 58/66 and the inner wall 142. Subsequently, the MR fluid 40 isforced into the MR fluid chamber 158 and forces the separator piston 154move toward the end wall 150, thereby compressing the gas within the gaschamber 162. Thereafter, when the compressive forces on the MR damper 34are removed, and/or extension forces are exerted on the MR damper 34(e.g., rebound motion), the compressed gas within the gas chamber 162forces the MR fluid 40 within the MR fluid chamber 158 back through thesubstantially U-shaped annular fluid flow channel 54 where the shearstrength, or shear stress, of the MR fluid 40 is controllably altered,as a result of the controlled strength of the magnetic flux generated bycoil(s) 66 and directed across both the portion of the channel 54passing between the core/coil 58/66 and the outer housing 140, and theportion of the channel 54 passing between the core/coil 58/66 and theinner wall 142. Accordingly, the compression (or jounce) and extension(or rebound) of MR damper 34 can be controlled. Moreover, when the coilcover(s) 82 is/are multi-section covers, as described herein, thecontrol ratio of the MR valve 50, and hence the MR damper 34, issignificantly increased.

Referring now to FIG. 11 , in various embodiments, the MR damper 34 cancomprise a cylindrical body 170 and a valve canister 174 formed ordisposed along an exterior side of the cylindrical body 170. In suchembodiments, the MR damper 34 additionally includes a conduit cap 178connected to ends of, and fluidly connecting, the cylindrical body 170and the valve canister 174. The valve canister 174 comprises an outerhousing 182 and an end wall 186 that seals the end of the valve canister174, and a separator piston 190 disposed within the valve canister 174.The separator piston 190 defines a MR fluid chamber 194 disposed on oneside of the separator piston 190 and a gas chamber 198 disposed on theother side of the separator piston 190. The MR valve piston 42 isdisposed within the interior of the cylindrical body 170. The portion ofthe cylindrical body interior disposed on the opposite side of thepiston 42 from the piston rod 46, and an interior of the conduit cap 178are at least partially filled with MR fluid 40 (not shown).

In such embodiments, the core 58 is disposed within the valve canisterbetween the MR fluid chamber 194 and the conduit cap 178 such that theannular fluid flow channel 54 passes between the core 58 and the fluxring 62, fluidly connecting the interior space of the conduit cap 178with the MR fluid chamber 194. In various embodiments the flux ring 62can comprise the outer housing 182, or in various other embodiments theflux ring 62 can be an independent structure disposed between the core58 and the outer housing 182. Additionally, in various embodiments thecore 58 can be a single piece core or in various other embodiments thecore 58 a multi-piece core. The core 58 includes one or more coilreservoir 78 formed therein. A respective conductor coil 66 is disposedwithin each reservoir 78 such that, when energized, each coil 66 willgenerate a magnetic flux field that will be directed across the fluidflow channel 54 along the portion of the channel 54 passing between thecore/coil 58/66 and the flux ring 62. Additionally, the MR valve 50 acoil cover 82 disposed over each coil 66. Each coil cover 82 can be asingle piece or a multi-section coil cover as described above withregard to FIGS. 1, 2, 3, 4, 5, 6, 7 and/or 8 .

In operation, when the MR damper 34 is compressed (e.g., jounce motion)the MR fluid 40 is moved within the cylindrical body 170 as the piston42 is moved toward the conduit cap 178. Consequently, the MR fluid 40 isforced through the conduit cap 178 and directed into the annular fluidflow channel 54 by a diverter dome 202 disposed within the conduit cap178 and connected to, or positioned adjacent, the core 58. As the MRfluid 40 passes through the fluid flow channel 54 the shear strength, orshear stress, of the MR fluid 40 is controllably altered, as a result ofthe controlled strength of the magnetic flux generated by coil(s) 66 anddirected across the channel 54. Subsequently, the MR fluid 40 is forcedinto the MR fluid chamber 194 and forces the separator piston 190 movetoward the end wall 186, thereby compressing the gas within the gaschamber 198. Thereafter, when the compressive forces on the MR damper 34are removed, and/or extension forces are exerted on the MR damper 34(e.g., rebound motion), the compressed gas within the gas chamber 198forces the MR fluid 40 within the MR fluid chamber 194 back through thefluid flow channel 54 where the shear strength, or shear stress, of theMR fluid 40 is controllably altered, as a result of the controlledstrength of the magnetic flux generated by coil(s) 66 and directedacross the channel 54 passing. Accordingly, the compression (or jounce)and extension (or rebound) of MR damper 34 can be controlled. Moreover,when the coil cover(s) 82 is/are multi-section covers, as describedherein, the control ratio of the MR valve 50, and hence the MR damper34, is significantly increased.

Referring now to FIGS. 9, 10 and 11 , although not specifically shown inthe various embodiments of the MR valve 50 illustrated, by way ofexample, in FIGS. 9, 10 and 11 , it is envisioned that, in variousembodiments, the ends of the respective fluid flow channel 54 can bechamfered, angled, funnel shaped or include a bezel to provide a largerdiameter at the ends from that of a central portion of the respectivefluid flow channel 54. As described above, the chamfered, angled, funnelshaped or bezelled ends are structured and operable to allow the MRfluid to enter and exit the respective fluid flow channel 54 more easilyand with less turbulence and/or disruption, thereby increasing theon-state force, and decreasing the off-state force of the MR fluidflowing through the channel 54, which in turn, further increases thecontrol ratio of the MR valve 34. Additionally, it should be noted thatin various embodiments wherein the respective housing (e.g., housing122, 140 and/or 182) comprises the flux ring 62, the MR damper 34 canreject heat quicker and easier than the embodiments wherein the MRdamper 34 includes a flux ring 62 that is disposed within the respectivehousing. Particularly, having the housing 38 function as the flux ring62 provides a shorter dissipation path for the heat generated within theMR damper 34. More particularly, the exposure of the outside of thehousing to the ambient environment helps maintain the housing/flux ring38/62 at a cooler temperature such that the housing/flux ring 38/62 willabsorb and dissipate the generated heat more efficiently.

The description herein is merely exemplary in nature and, thus,variations that do not depart from the gist of that which is describedare intended to be within the scope of the teachings. Moreover, althoughthe foregoing descriptions and the associated drawings describe exampleembodiments in the context of certain example combinations of elementsand/or functions, it should be appreciated that different combinationsof elements and/or functions can be provided by alternative embodimentswithout departing from the scope of the disclosure. Such variations andalternative combinations of elements and/or functions are not to beregarded as a departure from the spirit and scope of the teachings.

What is claimed is:
 1. A magnetorheological damper, said dampercomprising: a housing at least partially filled with amagnetorheological fluid; and a magnetorheological valve disposed withinthe housing, the magnetorheological valve comprising: a piston movablydisposed within the housing, the piston comprising: a magneticallypermeable core having at least one coil reservoir formed therein; atleast one conductor coil, each conductor coil disposed around a portionof the core within a respective one of the at least one coil reservoirformed within the core; a non-magnetically permeable end cap disposed onan end of the piston; and at least one coil cover, each coil coverdisposed over a respective one of the at least one coil; a magneticallypermeable flux ring; and a fluid flow channel defined between the fluxring and the at least one conductor coil cover, the fluid flow channelstructured and operable to allow a magnetorheological fluid to flowtherethrough, wherein the end cap comprises a plurality of openingsaligned with the fluid flow channel to allow the magnetorheologicalfluid to flow through fluid flow channel as the piston moves within thehousing.
 2. The damper of claim 1, wherein the at least one coil covercomprises at least one magnetically permeable section that provides aportion of an active length of the valve; and at least one magneticisolator section fabricated that provides at least a portion of aninactive length of the valve.
 3. The damper of claim 2, wherein a totalactive length of the valve is 60% to 95% of a total length of the fluidflow channel.
 4. The damper of claim 2, wherein the at least onemagnetically permeable section of the at least one coil cover isprovided by a portion of the core that extends over a portion of therespective coil reservoir.
 5. The damper of claim 1, wherein opposingends of fluid flow channel are chamfered.
 6. The damper of claim 1,wherein the piston comprises the flux ring such that the fluid flowchannel is formed within the piston, and wherein the openings within theend cap comprise a plurality of orifices formed radially inward from anouter periphery of the end cap.
 7. The damper of claim 6, wherein acircumferential edge of each orifice is chamfered.
 8. The damper ofclaim 1, wherein the housing provides and comprises the flux ring suchthat the fluid flow channel is formed between the piston and thehousing, and wherein the outer periphery of the end cap is scallopedsuch that the plurality openings are a plurality of semi-circularopenings formed around the outer periphery of the end cap.
 9. The damperof claim 8, wherein an arcuate edge of each orifice is chamfered.
 10. Avehicle suspension system, said suspension system comprising: amagnetorheological damper, said damper comprising: a housing at leastpartially filled with a magnetorheological fluid; and amagnetorheological valve disposed within the housing, themagnetorheological valve comprising: a piston movably disposed withinthe housing, the piston comprising: a magnetically permeable core havingat least one coil reservoir formed therein; at least one conductor coil,each conductor coil disposed around a portion of the core within arespective one of the at least one coil reservoir formed within thecore; a non-magnetically permeable end cap disposed on an end of thepiston; and at least one coil cover, each coil cover disposed over arespective one of the at least one coil; a magnetically permeable fluxring; and a fluid flow channel defined between the flux ring and the atleast one conductor coil cover, the fluid flow channel structured andoperable to allow a magnetorheological fluid to flow therethrough,wherein the end cap comprises a plurality of openings aligned with thefluid flow channel to allow the magnetorheological fluid to flow throughfluid flow channel as the piston moves within the housing.
 11. Thevehicle of claim 10, wherein the at least one coil cover comprises atleast one magnetically permeable section that provides a portion of anactive length of the valve; and at least one magnetic isolator sectionfabricated that provides at least a portion of an inactive length of thevalve.
 12. The vehicle of claim 11, wherein a total active length of thevalve is 60% to 95% of a total length of the fluid flow channel.
 13. Thevehicle of claim 11, wherein the at least one magnetically permeablesection of the at least one coil cover is provided by a portion of thecore that extends over a portion of the respective coil reservoir. 14.The vehicle of claim 10, wherein opposing ends of fluid flow channel arechamfered.
 15. The vehicle of claim 10, wherein the piston comprises theflux ring such that the fluid flow channel is formed within the piston,and wherein the openings within the end cap comprise a plurality oforifices formed radially inward from an outer periphery of the end cap.16. The vehicle of claim 15, wherein a circumferential edge of eachorifice is chamfered.
 17. The vehicle of claim 10, wherein the housingprovides and comprises the flux ring such that the fluid flow channel isformed between the piston and the housing, and wherein the outerperiphery of the end cap is scalloped such that the plurality openingsare a plurality of semi-circular openings formed around the outerperiphery of the end cap.
 18. The damper of claim 17, wherein an arcuateedge of each orifice is chamfered.
 19. A magnetorheological damper, saiddamper comprising: a housing at least partially filled with amagnetorheological fluid; and a magnetorheological valve disposed withinthe housing, the magnetorheological valve comprising: a piston movablydisposed within the housing, the piston comprising: a magneticallypermeable core having at least one coil reservoir formed therein; atleast one conductor coil, each conductor coil disposed around a portionof the core within a respective one of the at least one coil reservoirformed within the core; a non-magnetically permeable end cap disposed onan end of the piston; and at least one coil cover, each coil coverdisposed over a respective one of the at least one coil, wherein the atleast one coil cover comprises at least one magnetically permeablesection that provides a portion of an active length of the valve; and atleast one magnetic isolator section fabricated that provides at least aportion of an inactive length of the valve; a magnetically permeableflux ring; and a fluid flow channel defined between the flux ring andthe at least one conductor coil cover, the fluid flow channel structuredand operable to allow a magnetorheological fluid to flow therethrough,the fluid flow channel having chamfered opposing ends, wherein the endcap comprises a plurality of openings aligned with the fluid flowchannel to allow the magnetorheological fluid to flow through fluid flowchannel as the piston moves within the housing.
 20. The damper of claim19 wherein each of the end cap openings comprise a chamfered peripheraledge.